A Study on a Salt Clean-up with Solid Cathode- Perforated Ceramic Container

Electrorefining is a key technology of pyrochemical processing. The electrorefining is generally composed of two recovery steps: deposit of uranium onto a solid cathode and the recovery of actinide elements by a liquid cadmium cathode. After the operation of the liquid cadmium cathode, it is necessary to remove the remaining TRU (transuranic) elements from the molten salt before a treatment of waste salt or salt regeneration. In this study, we attempted to clean up a molten salt with a cathode of solid cathode-perforated ceramic container and a glassy carbon anode. LiCl-KCl eutectic salt was used as a medium of the electrolytic bath. Uranium and cerium were used as solutes, where uranium was used as a surrogate for the TRU elements. Initial contents of uranium and cerium in the salt were varied in the range of 0 to 5 wt. %. Electrolysis experiments were carried out by passing a constant current between the anode and the cathode at 500 deg. C. The solute contents were measured by using ICP (inductively coupled plasma-atomic emission) spectroscopy. The initial cathode potential was about -1.6 V. This value decreased with decreasing content of uranium in the salt. The electro-refiner was successfully operated and uranium in the molten salt was effectively recovered onto the cathode. (authors)